The present invention relates to a system for transmitting a voice simultaneously with image data and more particularly to a voice/image simultaneous communication apparatus which performs communication by converting a voice into digital data.
As a technique of transmitting a plurality of pieces of information by using the telephone line, a technique of transmitting a voice simultaneously with other information signals by securing less deterioration in voice quality is introduced in JP-B 55-28616.
In this prior art, information signals are transmitted within a central band portion having a flat characteristic in a telephone transmission band of from 0.3 kHz to 3.4 kHz and therefore, the quality of information signals can be maintained and in addition low frequency components and high frequency components of a voice can serve to lessen deterioration in voice quality.
However, in an application to, for example, facsimile wherein a modulation signal having a modulation band which occupies most of the transmission band of telephone line is transmitted as an information signal, the frequency-multiplexed simultaneous transmission of a voice signal and an information signal as in the aforementioned prior art is difficult to achieve.